dT’ is the time required to apply the control signal to
produce P1 MW. The signal will only be applied for dT’/2
however. Since dT’/2 is shorter than the PMS control time
interval, after dT’/2 seconds, the control signal will be
removed and the power output will remain unchanged for the
remainder of the PMS calculation interval. This is shown by
the horizontal curve just after dT’/2. P2 shows that a lower
power output is required, and the same control sequence is
implemented, this time however using a negative slope. P3
has the same value as P2 and thus no control signal need be
applied as shown by the horizontal line. The time to get from
P3 to P4 exceeds twice the PMS control time interval. Thus the
maximum duration for this control signal will be the PMS
calculation interval itself which is less than 50% of the
calculated time. Thus at no time do the PMS control signals
achieve full correction – they just successively bring the
system closer to the desired operating condition. The farther
away the desired value, the longer the control signal is
applied. This type of control is very common.